A gas operated autoloading firearm uses a portion of the gas from the cartridge being fired to power the mechanism to extract the spent case and insert a new cartridge into the rifle chamber. Energy from the gas is generally collected through a port in the firearm barrel. The high-pressure gas may impinge upon a piston head or “gas key” to provide the motion for unlocking the firearm action, extract and eject the spent case while cocking the hammer and having a spring return chambering a new cartridge of the firearm and locking the action. The gas port in the barrel needs to be placed a sufficient distance from the end of a barrel in order to obtain the desired pressure and time in the gas port for completing the extraction of the cartridge before the bullet leaves the end of the barrel.
Gas operated firearms commonly use either a solid gas piston or hollow “gas tube” driven by the combustion gas from a port in the firearm barrel near the muzzle of the barrel. The barrel is the same for both types. The port size and distance from the end of the barrel needs to be tuned for the operating parts and spring pressure. Many firearms, such as the AK-47, use a long-stroke piston system in which the piston is mechanically fixed to the bolt assembly and moves through the entire operating cycle. A short stroke system moves the piston separately from the bolt assembly. A direct impingement uses a hollow gas tube which allows gases to travel through it and the gas pushes on a gas key and unlocking the bolt.
The present invention is for a gas operated firearm barrel having a gas port angled through the wall thereof at an angle from adjacent the barrel muzzle rearward to the barrel bore to thereby allow the shortening of the barrel while maintaining the distance of the gas port bore opening from the barrel muzzle. The process of making a gas port in a barrel in accordance with the present invention is also taught.